1. Field of the Invention
The present invention generally relates to a low profile circuit device, and more particularly to a low profile circuit device having an improved surface-mounted device to decrease the entire height of the circuit devices of a liquid crystal display module.
2. Description of the Related Art
Due to the advance of electronic technology, especially for the popularity of portable electronic products, the requirements of light, compact and low-energy consuming display are gradually increasing. With the advantages of low-energy consuming, low-heat dissipation, light weight and non-luminescence, liquid crystal displays (LCD) have been widely used in the electronic products and even have replaced the traditional CRT displays.
An LCD basically comprises polarizers, glass electrodes and liquid crystal materials. The polarizers are made of the polarizer material sandwiched between two transparent films. The glass electrodes are made of high quality flat glass which is plated with a layer of conductive film of metallic oxidation. The molecules of liquid crystal material possess very strong electron conjugation moving ability. When the liquid crystal molecules are influenced by electric field, they are easily polarized to produce induced dipolar phenomena, thereby resulting in the displaying image in the LCD. The manufacturing process of LCD substantially includes the steps of injecting the liquid crystal material into the space between the two flat glasses with glass electrodes thereon, and adhering polarizer films onto the outer surfaces of the flat glasses so as to form the LCD cell. Then the driving circuits, controlling circuits, and backlight components etc. will be assembled to constitute an LCD module.
Now referring to FIG. 1, it depicts a schematic sectional diagram of a printed circuit board 13 in prior art which is attached to the LCD module and is provided with a surface mounted device 11 such as the driving integrated circuit and the controlling integrated circuit of the LCD. The surface mounted device 11 is electrically connected to and is mounted on the printed circuit board 13 by way of a bent lead 12. Typically, the height of the printed circuit board 13 is about 0.6 mm and the height of the surface mounted device 11 is about 1.2 mm, so the entire height H thereof is about 1.8˜2.0 mm.
Also referring to FIG. 2, it depicts a schematic sectional diagram of the prior art printed circuit board 13 connected to an LCD panel 31 by way of a flexible substrate 34. As shown in the drawings, since the printed circuit board 13 is attached against a back light module 32 beneath the LCD module by way of the flexible substrate 34, the height of the printed circuit board 13 and the height of the electronic devices thereon critically affect the thickness of the LCD.
Accordingly, there exist the needs for providing a low profile circuit device to decrease the thickness of an LCD module and further decrease the thickness of an LCD.